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Date: Mon, 1 Apr 1996 21:15:40 +1000
From: Bruce Evans <bde@zeta.org.au>
Message-Id: <199604011115.VAA15805@godzilla.zeta.org.au>
To: freebsd-current@freefall.freebsd.org, kuku@gilberto.physik.rwth-aachen.de
Subject: Re: calcru: negative time:
Sender: owner-current@FreeBSD.ORG
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>[deleted]
>calcru: negative time: -11929 usec
>calcru: negative time: -3909 usec
>calcru: negative time: -3842 usec
>calcru: negative time: -17709 usec
>calcru: negative time: -3480 usec

This is caused by hardclock() interrupt latency.  The problem is
especially noticable on i586's and i686's because any latency causes the
clock to go backwards; on i386's and i486's, the latency must be > 1
clock tick (10000 usec) to cause problems.  Normally the latency on
i586's is > 0 but < 10 usec and isn't detectable.  There must be bugs
elsewhere to cause latencies of more than a few tens of usecs.

Bruce